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Origins, introduction to and my perspective of the FreeForm™ modelling system. Written in 2002
Rapid prototyping
Context
Realisation
RP Additive
Adding material - Self supporting - Additional support
RP subtractive
CNC Machining - Manufacture and multiple copies
Context
FreeForm has real potential as an all round design tool from concept to production. It has proved this in many
other market sectors such as toys and consumer goods. Its software is continually being developed through working in partnership with many prominent design companies around the world and it is also
opening up and developing more markets to digital 3D which include heritage, conservation, medical and footwear. This can only add to increased demand for rapid prototyping.
A rapid prototyped model can focus in physical terms the intent of the whole design team, from artist to
engineers and from management to sales. The concept is therefore agreed with confidence, before committing to the costly manufacturing and tooling process. A Rapid prototype can be the physical
realisation that can determine a major change in direction, a detailed modification, or can reinforce original intention and complete the brief.
A 3D digital file has the potential for many outcomes; these can range from creating elements for an animation,
to providing the pattern for a plastic injection-moulding tool. Some forms may be used for several outcomes. Files in digital format can be analysed and quantified, tested and verified to give the
designer and company total confidence in the performance of the product being created.
If you have created a sculpture in real clay and you want to change the modelled form to a more permanent
material, it will enter a production process. To create a bronze the clay needs to be changed, through a casting process, to wax. The wax copy will be invested, bronze melted and poured. The bronze is
retrieved from the pit and the final chasing and repairing of the cast takes place. This final stage is a physical and intimate review of the form; marks and surface treatment applied now complete the
creative process.
Physical modelling and mark making on real material is a valuable and essential creative experience. It is a
primary form of conceiving, understanding and creating a design. The realisation of intent is a compromise between the creative ambition of the designer, his practical skill and the limitations of the
materials being used. A Rapid prototype is a valuable stage in the development of an idea whether to review, or to complete the process.
Realisation
New production technology is continually being developed through the essential need to improve accuracy and
reliability. To be able to understand and predict material performance through analytical applications has enhanced the skills of the manufacturer and designer. Creative software will continue to push
the boundaries of these processes. There are however some fundamental elements that will always affect a design, one being undercuts that can affect the parting of mould and the other is the
characteristics and behaviour of the materials being used to form the finished item.
In most design cases the main aim for this process is to clinically generate a digital model for review,
verification, and for the production of moulds, or tools, to enter a production process. As you would expect product tolerances are very important in a lot of engineering based product manufacture,
making aircraft components is one example for the need for accuracy.
Over the last 3 years there have been huge advances in the performance of materials and technology used, for
example the Zcorp printer has moved from using a starch based material to a much finer plaster based powder, this has been improved further to now include the capability to print models in colour.
Recently a new Zcorp system has been launched that can build a part 600x500x400mm. A completed model can be finished with a wax dipped coat, or infiltrated with a liquid adhesive which gives
strength to the model, when this is done further hand work can be done to the model if required.
Basic principles
To Rapid Prototype is to reproduce accurately in solid form a computer generated 3 dimensional drawing. This
can be achieved in 2 fundamental ways, adding material where there was none and subtracting material from a block.
A digital file can represent the positive form or a negative form in the shape of a piece mould, this is a
choice is made before a file is exported.
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